The truth is to be a good bodybuiler means being selfish. needing the time to rest, needing the time to eat, needing the time to lift, all at the same time of having a full time job, but "ME" time goes out the window when you have a helpless 100% dependant child. It all depends on how much you want to dump on the wife. Those that say their lives didn't change are the ones that never invested in the kid and dumped all of the work on the mom. Ask the mom if her lifestyle didn't change. lol.
But you will adjust, once the child is a little more able to talk, walk eat on their own, you can start finding time. But when the baby needs to be changed 12 times in a 24 hour period without any set schedule, it totally messes with what you used to call "ME" time.
The first thing, be a great Partner to your wife, then be a great dad, after that be a great bodybuilder.